Casing scrapers and feelers



July 26, 1955 2,713,913

T. M. RAGAN CASING SCRAPERS AND FEELERS Original Filed Jan. 11, 1949 2Sheets-Sheet l 3 31 2 /04 145 M .IQAGAN,

INVEN TOR.

15 firraelvsys July 26, 1955 T. M. RAGAN 2,713,913

CASING SCRAPERS AND FEELERS Original Filed Jan. 11, 1949 2 Sheets-Sheet2 B 22a. 6. 10a 17 5:: 1% Q ":ai t

v Z nfiz z WWW IQTTOQNEYS United States Patent 6 CASING CRAPERS ANDFEELERS Divided and this application March 16, 1953, Serial No.342,446

7 Claims. (Cl. 166-173) The present invention relates to devices forcleaning the inner walls of well casings, liners and similar conduits,and more particularly to casing scrapers capable of removing a film orcake of hardened cement, synthetic resin, mud, paraffin, gunshot burrs,bullets, and various other types of undesired materials from the wallsof such conduits.

This application is a division of my application for Casing Scrapers andFeelers," Serial No. 70,323, filed January 11, 1949, now abandoned.

An object of the invention is to provide improved devices for scrapingthe walls of well conduits.

Another object of the invention is to enable the entire circumference ofthe wall of the well conduit to be scraped by longitudinally moving thescraping tool, and without rotating it. The scraping action is alsoperformable by rotating the tool.

A further object of the invention is to provide a device capable ofscraping the entire circumference of a well conduit wall bylongitudinally moving the device, in which the device tends to centeritself automatically in the well conduit.

Yet another object of the invention is to provide improved stop devicesfor limiting the extent of lateral out ward expansion of casing scrapercutters and for holding the cutters in assembled relation on the body ofthe scraper.

Still another object of the invention is to provide stop devices forlimiting the extent of lateral outward expansion of casing scrapercutters, which do not materially weaken the body of the scraper orthecutters themselves.

Another object of the invention is to provide stop devices for limitingthe extent of lateral outward expansion of casing scraper cutters, inwhich the stop devices are arranged in such manner as to avoidinterference with one another.

A further object of the invention is to provide a casing scraper capableof being both assembled and dismantled in a simple and facile manner.

A further object of the invention is to provide a casing scraper capableof acting as a feeler in locating bullets and other restrictions in awell conduit as an incident of moving the tool longitudinally in theconduit.

Yet another object of the invention is to provide a casing scraperhaving a large number of cutting teeth and tooth surfaces, therebyincreasing the effective life of the cutters.

This invention possesses many other advantages, and has other objects,which may be made more clearly apparent from a consideration of severalforms in which it may be embodied. Such forms are shown in the drawingsaccompanying and forming part of the present specification. These formswill now be describedin detail, illustrating the general principles ofthe invention; but it is to be understood that such detailed descriptionis not to be taken in a limiting sense, since the scope of the inventionis best defined by the appended claims.

Referring to the drawings:

Figure l is a side elevation of a casing scraper disposed in a wellcasing or similar conduit;

Fig. 2 is an enlaraged front elevation of part of the scraper shown inFig. 1;

Fig. 3 is an enlarged cross-section taken along the line 33 on Fig. 1;

Fig. 4 is a longitudinal section taken along the line 44 on Fig. 2;

Fig. 5 is a front elevation of part of a modified form of casingscraper;

Fig. 6 is a longitudinal section taken along the line 66 on Fig. 5;

Fig. 7 is a cross-section taken along the line 77 on Fig. 5.

In the form of invention disclosed in Figs. 1 to 4, inclusive, agenerally cylindrical, elongate scraper body 10 has its upper pin 11threaded into the lower end of a string of drill pipe, or other tubularstring A. The lower end of the body may be formed as a threaded box 12attachable to the upper pin 13 of the body 14 of a drill bit. The drillbit may be omitted, if desired, in performing a scraping operation on astring of well casing B, or other well conduit in which the tool is tobe run.

The elongate body 10 has a central passage 15 extending throughout itslength, to enable circulating fluid to be pumped down the drill string Aand completely through the elongate body 10. The fluid can flow throughthe usual central passage 16 in the drill bit, when a drill bit is used,for discharge from the latter and upward flowing around the body 10 toflush cuttings and other materials to the top of the well casing. In theabsence of a drill bit, the circulating fluid exits from the lower endof the body 10 for upward passage therearound to the top of the wellcasing.

The body 10 is provided with a plurality of sets of scraper blades orcutters 17 that are adapted to be urged outwardly against the inner wallof the casing B and effectively scrape any foreign substances therefrom.The cutters are preferably arranged around the body in such manner as tocover collectively substantially the entire circumference of the wellcasing. Because of this arrangement, the entire surface of the casingwall can be scraped merely by moving the scraping tool longitudinallywithin the casing and without rotating it. This 360 degree coverage ofthe casing wall by the cutters 17 may be obtained by offsetting sets 18,19, 29 of scraper cutters with respect to one another, in the mannerdescribed hereinafter.

Each scraper blade or cutter 17 is slidably mounted within alongitudinally extending groove 21 formed in the body 19 of the tool.The longitudinal, central plane of this groove may be disposed radiallyor" the tool body or it may be ofiset with respect to this radial plane,if desired. Each groove has top and bottom end walls 22, 23 parallel toone another, and also parallel side walls 24, 25 extending outwardlyfrom the bottom or base 26 of the groove. The corners 27 formed betweenthe side walls and end walls may be rounded, in order to facilitateformation of the grooves 21 by use of an end mill. It is to beappreciated, however, that these corners may be formed as right angles,if desired.

Each cutter 17 has side Walls 28, and also top and bottom end walls 29,making a sliding fit with the companion walls of the groove 21, in orderto prevent tilting of the cutter and confine its path of movement to asrtaight line within the groove. If the corners 2 7 of the groove arerounded, the corners 30 of the cutter are correspondingly rounded. Thecutter has external helical, longitudinally spaced teeth 31, whose outersurfaces are curved to conform to the curvature of the inner wall of thewell conduit B being scraped. As

depicted in Figs. 1 and 2, the teeth 31 slope downwardly toward theright, with their lower edges preferably provided with hardfacingmaterial 32, such as tungsten carbide, in order to insure long wear andlife of the cutter teeth.

In order to prevent catching of the cutters 17 in collar spaces in thecasing string B, and to facilitate insertion of the tool within thecasing, the upper and lower outer ends 33 of each cutter are beveled orinclined to a substantial extent. faces 28 of the cutter, which projectbeyond the body 10, from engaging certain obstructions, such as bullets,in the well casing and be blocked thereby, the outer portions 34 of thesides of each cutter are beveled or inclined to a substantial extent.

Each cutter 17 is urged outwardly by one or more helical springs 35.Each spring is disposed within a socket 36 formed in the cutter, itsouter end bearing against the base of the socket and its inner endagainst the base 26 of the groove 21. to 4, inclusive, four compressionsprings 35 are utilized for urging each cutter outwardly, the springsbeing disposed in the region of the cutter corners. It is to beunderstood, however, that the number of springs, their arrangement, andthe size of each spring can be varied,

depending upon the outward force on the cutter desired.

Each cutter 17 is held in assembled relation on the body 10 and itsoutward expansion under the influence of the springs'35 limited by astop device. In Figs. 1 to 4, inclusive, this stop device takes the formof a single stop pin or rod 37 extending transversely and lengthwisethrough an enlarged central hole 38 in a cutter, both the hole 38 andthe rod 37- being substantially parallel to the base 26 of the groove21. One end 39 of the rod is received within a bore 4 communicating withthe larged cutter hole 38, and into the other body bore 40.

When fully inserted, the end 42 of the rod may be essentially clear ofthe side of the recess 44. This rod 37 is prevented from inadvertentremoval by a cap screw 45 threaded into a hole 46 in the body 10disposed at an angle to the red, the head 47 of the screw being Io-Similarly, to prevent the side As disclosed in Figs. 1

cated within the recess 44 adjacent the rod, in order to prevent endwiseremoval of the latter, so long as the screw is in place. Loosening ofthe screw 45 may be prevented by a lock washer 48 clamped between thescrew head 47 and the body shoulder 49 forming one wall of the recess44.

It is apparent that when the stop rod 37 is in place, outward movementof the cutter 17 under the influence of the springs 35 is limited byengagement of the inner wall portion of the transverse hole 38 with therod. In

the normal operation of the tool, its insertion into the casing B forcesthe cutter 17 inwardly against the action of the springs 35, in order tofree the cutter from contact with the rod 37, allowing radial movementof the cutter both inwardly and outwardly, to conform to the conditionsin the casing (Figs. 3 and 4).

The cutters 17 in each set are preferably symmetrically disposed aroundthe scraper body 19 and lie in the same central cross-sectional plane.Thus, as illustrated in the drawings, the radial planes of the cuttersare substantially 120 degrees from one another, thereby effectivelycentering the scraping tool within the Well casing B. The width of eachgroove 21 and the arcuate extent of the cutter teeth 31 are such as tocover a substantial portion of the circumference of the wall of the wellconduit B. Since three sets 18, 19, 21} of cutters are disclosed in thedrawings, the cutter teeth in each set preferably subtend a cumulativearc of substantially 120 degrees. That is, the teeth 31 on each cutter17 extend arcuately about 40 degrees around the tool body 10. I

Since each set of cutters does not cover substantially the fullcircumference of the tool and easing being scraped, the sets 18, 19, 20of cutters are offset from one another, to insure that they cumulativelycover the entire circumference of the tool. Thus, inthe specificarrangement disclosed in the drawings, the intermediate set 19 ofcutters 17 is displaced approximately 40 degrees with respect to theupper set 18, 'whereas the lower set 20 of cutters is displaced in thesame direction substantially 40 degrees with respect to the intermediateset 19. By virtue of this arrangement, it is apparent that the cutters17 in all sets 18, 19, 20 jointly cover substantialiy the fullcircumferential extent of the body and the well conduit.

It is to be understood that the number of sets of cutters can be varied,if desired, as well as the arcuate extent of each cutter; so long as thecutters cumulatively cover essentially the entire circumference of thetool body. An effective scraping action can occur even if the cutterscumulatively cover slightly less than the. full circumference of thebody; so long as the arcuate gaps between the cutters are not too great.

With the stop arrangement disclosed, the parts can be appropriatelyassembled and also dismantled very readily. The stops 3'7, themselves,do not cause any material weakening of the scraper body, as becomesevident from an inspection of Fig. 3. Also, the stop devices aredisposed in suchmanner as to avoid interference with one another bothduring the assembly and dismantling of the parts. Each cutter 17 can bemounted in place-independently of the other cutters and withoutinterference.

The uniform distribution of the cutters 17 about the axis of the toolinsures that the cutters will'center. the tool within the well casing.In this respect, the centering action is exceedingly effectivebecause ofthe several sets of cutters used.

In the operationof the tool, it is lowered in the well casing. Duringthis lowering action, the cutter teeth 31 will scrape the cement sheath,mud cake, or any other foreign substances from the Wall of the wellcasing B. Rotation of the drill string A and tool may not be necessary,since, so long as the tool can be lowered through the well casing,assurance is bad that the entire circumference of the casing is beingcleaned, because the cutter teeth 31 collectively cover essentially afull circle. When a restriction in the casing is reached, which cannotbe removed merely by iongitudinal movement of the tool, evidence of thisfact is transmitted to the operator by the inability to further lowerthe tool. When this condition arises, the tool can be rotated, with thecutters 17 acting upon the restriction until it is removed. During suchrotation, the tool will also be gradually lowered to insure completecleaning of the Wall of the well casing B; Whether the restriction inthe casing consists of a gunshot burr, a bullet, a cement or plasticsheath, or merely of a mud cake. During the scraping operation, eitherby longitudinal movement or by rotation, circulating fluid is pumpeddown the drill string A and through the scraper body to flush thecuttings to the top of the well bore.

It is evident that the tool functions. as a feeler as well as a casingscraper, since it indicates the presence of restrictions in the wellcasing as it is being moved longitudinally therewithin.

In Figs. 5, 6 and 7, a modified form of spring arrange ment and stopdevice is shown for each or the cutters. Instead of a single stop pin.extending transversely through the enlarged hole of the cutter, as inFigs. 1 to 4, longitudinally spaced upper and lower stop pins 37a areemployed at the upper and lower ends of the cutter.

These pins extend through enlarged holes 38a in the cutters, and areheld in place by cap screws 45a, in essentially the same manner as inthe other form of the invention. The springs 35, however, instead ofbeing mounted in the region of the corners of the cutters, are mountedin sockets 36:: formed in the medial portion of the cutters, as clearlyshown in Figs. 5, 6 and 7. In all respects, however, the operation of atool with the cutters disclosed in Figs. 5, 6 and 7 is the same as inthe form of invention shown in Figs. 1 to 4, inclusive.

The inventor claims:

1. In a casing scraper: a main body adapted for attachment to a drillstring, said body having a groove therein defined by top, bottom andside body walls; a cutter slidable laterally in said groove engaging allof said walls to prevent longitudinal and transverse movement of saidcutter with respect to said body, said cutter being guided in suchmovement by all of said walls, said cutter having longitudinally spacedhelical teeth; means normally urging said cutter laterally outwardly;and stop means carried by said body and extending through said cutterfor limiting the extent of outward movement of said cutter.

2. In a casing scraper: a main body adapted for attachment to a drillstring, said body having a groove therein defined by top, bottom andside body walls; a cutter slidable laterally in said groove engaging allof said walls to prevent longitudinal and transverse movement of saidcutter with respect to said body, said cutter being guided in suchmovement by all of said walls, said cutter having longitudinally spacedhelical teeth; means normally urging said cutter laterally outwardly;and stop means carried by said body for limiting the extent of outwardmovement of said cutter, said stop means comprising a member extendingthrough a hole in said cutter and into said body.

3. In a casing scraper: a main body adapted for attachment to a drillstring, said body having a groove therein defined by top, bottom andside body walls; a cutter slidable laterally in said groove engaging allof said walls to prevent longitudinal and transverse movement of saidcutter with respect to said body, said cutter being guided in suchmovement by all of said walls, said cutter having longitudinally spacedhelical teeth; means normally urging said cutter laterally outwardly;and stop means carried by said body for limiting the extent of outwardmovement of said cutter, said stop means comprising a member extendingtransversely of said groove through an enlarged transverse hole throughsaid cutter, said hole being larger in a direction longitudinally ofsaid body than said member to prevent the top and bottom portions ofsaid hole from engaging said member.

4. In a casing scraper: a main body adapted for attachment to a drillstring, said body having a groove therein defined by top, bottom andside body walls; a cutter slidable laterally in said groove engaging allof said walls to prevent longitudinal and transverse movement of saidcutter with respect to said body, said cutter being guided in suchmovement by all of said walls, said cutter having longitudinally spacedhelical teeth; means normally urging said cutter laterally outwardly;stop means carried by said body for limiting the extent of outwardmovement of said cutter, said stop means comprising a member extendingthrough a hole in said cutter and into said body, said hole being largerin a direction longitudinally of said body than said member to preventthe top and bottom portions of said hole from engaging said member; andmeans threaded into said body and engageable with said member forpreventing its removal from said hole.

5. In a casing scraper: a main body adapted for attachment to a drillstring, said body having a groove therein defined by top, bottom andside body walls; a cutter slidable laterally in said groove engaging allof said walls to prevent longitudinal and transverse movement of saidcutter with respect to said body, said cutter being guided in suchmovement by all of said walls, said cutter having longitudinally spacedhelical teeth; means normally urging said cutter laterally outwardly;and stop means carried by said body for limiting the extent of outwardexpansion of said cutter, comprising a rod extending across said groovebetween opposed walls of said groove, said cutter having a holetherethrough substantialiy larger in cross-section than said rod andthrough which said rod projects, said hole being sufficiently large toprevent engagement of said cutter with said rod in a directionlongitudinally of said body.

6. In a casing scraper: a main body adapted for attachment to a drillstring, said body having circumferentially spaced grooves therein, eachgroove being defined by top, bottom and side body walls; a cutterslidable laterally in each groove engaging all of said walls to preventlongitudinal and transverse movement of said cutter with respect to saidbody, each cutter being guided in such movement by all of said walls,said cutter having longitudinally spaced helical teeth; means normallyurging each of said cutters laterally outwardly; and stop means carriedby said body for limiting the extent of outward expansion of eachcutter, comprising a rod extending across each groove between the sidewalls of said groove, said cutter having a hole extending therethroughbetween its sides substantially larger in crosssection than said rod andthrough which said rod projects, said hole being sufliciently large toprevent engagement of said cutter with said rod in a directionlongitudinally of said body.

7. In a casing scraper: a main body adapted for attachment to a drillstring, said body having circumferentially spaced grooves therein, eachgroove being defined by top, bottom and side body walls; a cutterslidable laterally in each groove engaging all of said walls to preventlongitudinal and transverse movement of said cutter with respect to saidbody, said cutter being guided in such movement by all of said walls,said cutter having longitudinally spaced helical teeth; means normallyurging each of said cutters laterally outwardly; and stop means carriedby said body for limiting the extent of outward expansion of eachcutter, comprising a rod extending across each groove between the sidewalls of said groove, said cutter having a hole extending therethroughbetween its sides substantially larger in cross-section than said rodand through which said rod projects, said hole Ill) being suflicientlylarge to prevent engagement of said cutter with said rod in a directionlongitudinally of said body, said rods and holes lying in substantiallythe same central cross-sectional plane.

References Cited in the file of this patent UNITED STATES PATENTS1,764,373 Wells et al June 17, 1930 2,184,393 Luccous Dec. 26, 19392,272,405 Grant et a1 Feb. 10, 1942 2,464,390 Hammer Mar. 15, 1949

